1. Field of the Invention
The present invention relates to a method of producing a muffler for use with an internal combustion engine or the like which comprises an assembly of plates and tubes rigidly connected together and, more particularly, to a method which forms an eyelet in a predetermined location of a plate and inserts a tube thereinto to set up rigid connection therebetween.
2. Description of the Prior Art
A prior art muffler for an internal combustion engine or the like includes end walls which define axially opposite ends of a cylindrical casing. The interior of the casing is divided into a plurality of chambers by partition walls. Various tubes extend along the axis of the casing into, out of and within the casing while being supported by the various walls. Typical examples of the techniques heretofore employed to rigidly connect the plates and tubes may be spot welding and arc welding. However, a muffler manufactured by such a method is susceptive to corrosion due to the influence of heat. In light of this, Japanese Patent Publication No. 57-3805/82 and the parallel U.S. Pat. No. 3,921,754 issued Nov. 25, 1975, disclose a procedure in which a tube mounted in a plate is pressed from the opposite sides along its axis to form bulges at opposite sides of the plate and, then, the bulges are crimped to set up a rigid assembly of the tube and plate. A problem has existed in this method in that the tube has to be supported by a special metal core to be thereby prevented from being collapsed radially inwardly, resulting in an increase in cost and intricate assembling work.